NOTES 557 ton and Overhoff state: "Very numerous attempts were made to condense phthalimidohalogenoacetones with ethyl sodiochloromalonate and indeed with ethyl sodiomalonate itself under various conditions, but all were in vain. The halogenoacetones reacted exothermically with the sodiomalonates with rapid elimination of the sodium halide, but normal condensation did not occur, the products consisting for the most part of highly pigmented resins."The coupling of III with sodium diethylmalonate was studied in several solvents under various conditions and was found to yield several products. At refluxing temperature in alcohol sodium bromide was formed, but attempts to crystallize a product from alcohol, ether, and chloroform failed. A very small amount of material was crystallized from acetone, but was not studied further. When III was added as a solid to an alcoholic solution of sodium diethylmalonate at room temperature the reaction mixture crystallized spontaneously.The material (obtained in high yield, but not the desired product) was recrystallized from 95% ethanol in which it is only slightly soluble, m.p. 278-279°. A sample was prepared for analysis by recrystallization from W,W-dimethylformamide by addition of water and also from alcohol-water.The analysis suggested phthalimide (calculated
Die Synthese der eingeebneten dimethano-verbruckten Tribenzotropone 4a und b wird beschrieben. Reaktivitat und Spektren der bootformigen und der eingeebneten Verbindungen 3 und 4 werden verglichen. Im Gegensatz zu 3 laBt sich 4a an der Carbonylgruppe des Siebenrings nicht nach Huang-Minlon reduzieren. Beim Ubergang von 3 zu 4 beobachtet man sowohl eine langwellige Verschiebung der entsprechenden C = 0-Valenzschwingungen im IRals auch der Maxima ini UV-Spektrum.
Studies on Seven-Membered Ring Systems, XI') Synthesis of Flattened Tribenzotropones and their Comparison with Boat-shaped Analogous CompoundsThe synthesis of the flattened dimethano-bridged tribenzotropones 4a and b is described. The reactivity and spectra of the boat-shaped and flattened compounds 3 and 4 are compared. In contrast to the carbonyl group in 3, the carbonyl group in the seven-membered ring of 4a cannot be reduced by a Huang-Minlon reaction. In comparing 4 with 3 a shift of the corresponding C-0-stretching frequencies in the i.r. and the maxima in the U.V. spectra to longer wavelengths is observed. Tribenzocycloheptatriene (systematische Bezeichnung 9H-Tribenzo[u,c,e]cycloheptene) und Tribenzotropone (9H-Tribenzo[a.c.e]cycloheptenone(9)) bevorzugen im allgemeinen eine Konformation mit bootformigem Siebenring,). Stereochemische Studien an konformativ starren 1.2.3 .4-Tetraphenyl-9H-tribenzo-[a.c.e]cycloheptenen hatten bemerkenswerte, konformativ bedingte Reaktivitatsunterschiede zwischen 9a-und 9e-substituierten4) Derivaten aufgezeigt. Bei deren Umsetzungen treten wahrscheinlich ebenfalls bootformige Zwischenstufen auf 1.2.5.6). 1) X . Mitteil.: W. Tochtermnnn und G . H . Schmidt, Liebigs Ann. Chem. 754, 90 (1971). 2) Auszug aus den Dissertationen C. Degel und G . H. Schmidt, Univ. Heidelberg 1971. 3) ubersicht: W . Tochtermann, Fortschr. chem. Forsch. 15, 378 (1970). 4) a = quasi-axiale, e = quasi-aquatoriale Stellung eines Substituenten am C-Atom 9.
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